I, too, have been using Core-Plus Mathematics since 1999. My school in Maine is standards-based and Core-Plus fits quite nicely with our philosophy of integrated math and problem-based approach. We originally chose to go with Core-Plus because it was best aligned with our state standards and it had the best cohesive approach and rigor. We're lucky that it aligns so well with the Common Core standards and practices. I've taught both traditional algebra, geometry, etc, and Core-Plus integrated math classes. I can't imagine teaching a non-integrated math class anymore!Pam